Breathing assistance apparatus

ABSTRACT

A nasal cannula assembly is disclosed having a face mount part, in use resting against a user&#39;s face, which includes at least one nasal prong capable of being fitted into a person&#39;s nares. The cannula assembly also includes a manifold part, in fluid communication with the face mount part, having a single horizontal side gases entry. In particular, this cannula assembly is for supplying heated, humidified gases to a patient suffering from COPD. A tie or lanyard is disclosed for use with a breathing assistance apparatus such as a nasal cannula, face or nasal mask or tracheostomy connector. The tie or lanyard transfers the weight of the conduits supplying gases to the breathing assistance apparatus from the breathing assistance apparatus and distributes it onto the neck of the patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/592,069, filed Aug. 22, 2012, which is a continuation of U.S. patentapplication Ser. No. 13/187,209, filed Jul. 20, 2011, and issued as U.S.Pat. No. 8,267,092 on Sep. 18, 2012, which is a continuation of U.S.patent application Ser. No. 12/389,017, filed on Feb. 19, 2009, andissued as U.S. Pat. No. 8,220,463 on Jul. 17, 2012, which is acontinuation of U.S. patent application Ser. No. 10/855,146, filed onMay 27, 2004 and issued as U.S. Pat. No. 7,493,902 on Feb. 24, 2009,which claimed the priority benefit under 35 U.S.C. § 119 of New ZealandPatent Application No. 526,362, filed on May 30, 2003. Each of theseapplications is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates particularly, though not solely, to thedelivery of high flow humidified pressurized oxygen and/or air to apatient in need of respiratory support by way of a nasal cannula

Description of the Related Art

Nasal cannula generally consist of entry tubing, either symmetric orsingle sided that lies across the upper lip. Protruding from this tubingare open ended prongs which extend into the nares of the patient todeliver oxygen. Nasal cannulae have the advantage of being morecomfortable and acceptable than a facemask to most patients. Theexisting market for nasal cannula is well serviced by devices suitablefor the delivery of gases in the 0 to 5 liter per minute range. Thesedevices are typically supplied by a double entry lumen of small diameter(2-3 mm range) that supplies both sides of the nasal cannula andprovides even airflow to each nasal prong. These devices work well forthe delivery of low humidity gas flows of between 0 to 5 liter perminute and have been well received by patients over the last 30 years.

Hudson Respiratory Care Incorporated manufactures a nasal cannula thatis disclosed in U.S. Pat. No. 2,868,199 that consists of a single flowentry nasal cannula. This single flow entry has the advantage of beingunobtrusive, and more relevant to delivering humidity than a dual flowentry style of nasal cannula, simply due to the advantage of flow ratesand surface area for heat loss. The single flow entry is on the leftside only, which causes the user difficulty in use if the flow source ison the opposite side of the user requiring longer lengths of tubing andcausing the tube to cross the body. The cannula itself is manufacturedas one part only, of PVC plastic. This product is not designed fordelivering high flow or high humidity gases. The nasal prongs are lessthan 3 mm in diameter resulting in noise and high velocity jetting ofgas causing severe irritation at high flows. These cannulae aredifficult to clean inside, are uncomfortable, and the prongs are toorigid for extended therapies.

U.S. Pat. No. 3,754,552 of Sandoz-Wander, Inc. discloses a nasalcannula, having two nasal prongs, adapted for the intake of therapeuticgas from either the right or left side of the patient. Here the nasalcannula has a bore within it that feeds each prong. The bore is able toreceive a tube for supplying gases to the cannula in either end and inuse a plug is required to obstruct the unused end.

Innomed Technologies, Inc. manufactures a nasal cannula device calledthe NASALAIRE™. This nasal cannula is a dual flow entry style cannulawhere two large tubes come from behind the ears, through the field ofvision to the upper lip. In this device air or oxygen travels down awide bore conduit to the nasal cannula. The NASALAIRE™ creates aphysical seal between the nares and itself, and relies on the absence ofleaks around itself and the nares to deliver pressure supplied by acontinuous positive airway pressure (CPAP) blower to the airway of thewearer. The wearer is required to breathe in and out of the NASALAIRE™,thereby rebreathing some of the exhaled air from the lungs. TheNASALAIRE™ is not designed to deliver humidified gases to the patient,being unheated and without insulation of any type. The NASALAIRE™cannula is uncomfortable especially if a patient rests on the tube, aswould happen during sleep, and is also obtrusive.

The new application of high airflow extended therapies using nasalcannulae generally result in the nasal cannula reaching temperatures inexcess of 35 degrees C. Usually cannulae are made from soft polymericmaterial (for example, silicone) that absorbs heat and does not breatheand therefore sweat is generated under the contact points with the skin.This heat in combination with the polymeric materials waterproofproperties results in sweat being trapped against a patient's skin andthe patient has the sensation of overheating. The trapped sweat isuncomfortable and could lead to rashes.

Oxygen is generally supplied as a dry gas, but it is well known in theart to either heat and/or humidify gases before delivering them forbreathing by a patient. In particular when delivering oxygen, or anoxygen air mixture, it has proven beneficial to humidify the gasesfirst. In WO 01/41854 of Vapotherm, Inc. a system is disclosed thatallows the delivery of humidified oxygen through a nasal cannula. Thissystem uses a narrow bore conduit and nasal cannula with a highresistance to gas flows, thereby requiring the oxygen be of a highpressure. Air, as well as oxygen, can also be passed down the conduitand nasal cannula and it too must be of a high pressure. This systemallows the delivery of high flows of oxygen enriched air to the patient,but is limited in the flows achievable due to the narrow bore of thecannula resulting in high resistance gas flow and excessive velocity andnoise upon exiting the cannula. Furthermore, the narrowness of the nasalcannula in this system allows the patient to easily expire gases fromtheir nostrils as there is a reasonable gap between the prongs and thepatient's nares. Thus positive airway pressure is not created and assuch this cannula is not suitable for the treatment of Obstructive SleepApnea (OSA).

In breathing circuits that supply respiratory gases to a patient by wayof a patient interface, such as a nasal cannula, mask or tracheal tube,it is common to have a heated breathing circuit or tube deliveringheated and humidified gases to the patient, followed by a short lengthof non-heated tube close to the patient. This unheated tube may be ashort unheated extension tube or catheter mount. The unheated section oftube is usually intended to be very flexible to reduce torsion orpulling on the patient interface, to allow the gases to cool slightlytowards the dew point of the gas, and also to eliminate hot surfacetemperatures near the patient. As this tube is unheated the temperatureof the tube walls are colder than the dew point temperature of the gas,as a result the vapor in the gases passing near these walls will beginto condense out. Over time a build up of condensate close to the patientmay lead to a build-up of bacteria which may cause infection. Build upof condensation may also create noise, such as gurgling, which may wakea patient, and in extreme circumstances the fluid build up may causedrowning.

When providing humidified gases to a patient it is common to use aheated breathing circuit (tubing). This circuit is heavy and can dragand pull on the patient interface. This is more pronounced if thepatient is mobile and can be painful and/or dangerous if the patientinterface is invasive such as an endotracheal tube. It is common to usea short flexible tube between the heated circuit and patient interfaceto reduce any torque or twisting. In order to stop the weight pulling onthe patient interface, circuit hangers are occasionally used. This is alarge extendable metal arm to take the weight. It also has been known inthe art to clip part of the tubing to the patient's clothes orbedclothes. Both of these solutions have been found to be quiteunsuitable for mobile patients especially when sleeping and turning inbed.

With patient interfaces such as nasal cannulae the stability of thenasal prongs on the face is very important, as movement of the prongswithin the nares can cause severe irritation. Current methods employedto retain a single entry nasal cannula on the face use a simple elasticband of material around the back of the patients head. This is prone torotating the nasal cannula relative to the patient's head especiallywhen turning ones head on a pillow. This rotation causes the prongs movewithin the nares, irritating this sensitive area.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a breathingassistance apparatus which goes someway to overcoming the abovementioned disadvantages or which will at least provide the public auseful choice.

Accordingly in a first aspect the present invention consists in a nasalcannula assembly adapted to deliver gases to a patient comprising: aface mount part, including at least one nasal prong capable of beingfitted into at least one of said patient's nares, a removable gases flowmanifold part in use in fluid communication with said face mount part,said manifold part having a single horizontal side gases entry, in use,in fluid communication with said transport means.

In a second aspect the present invention may broadly be said to consistin a breathing assistance apparatus comprising: a pressurized source ofgases, humidification means adapted to, in use, be in fluidcommunication with said source of gases and adapted to in use humidifysaid gases, humidified gases transport means adapted to, in use, be influid communication with said humidification means and adapted to in useconvey said humidified gases, heating means disposed within saidtransport means and adapted to in use heat said gases as they passthrough said transport means, and nasal cannula, adapted to deliver saidhumidified gases to said patient, said nasal cannula comprising a facemount part, including at least one nasal prong capable of being fittedinto at least one of said patient's nares, a removable gases flowmanifold part in use in fluid communication with said face mount part,said manifold part having a single horizontal side gases entry, in use,in fluid communication with said transport means.

The invention consists in the forgoing and also envisages constructionsof which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described withreference to the accompanying drawings.

FIG. 1 is an illustration of a respiratory humidifier system that may beused with the nasal cannula assembly of the present invention.

FIG. 2 is a perspective view of a first form of the nasal cannulaassembly of the present invention.

FIG. 3 is an exploded perspective view of the first form of the nasalcannula assembly of FIG. 2, showing two parts making up the nasalcannula, a face mount part and gases flow manifold part attached totubing supplying gases to the patient.

FIG. 4 is a perspective view of a second form of the nasal cannulaassembly of the present invention, showing tubing providing a gasessupply to a gases flow manifold part and face mount part when inconnection.

FIG. 5 is a perspective view of the second form of the nasal cannulaassembly of FIG. 4 where the gases flow manifold part is disengaged fromthe face mount part.

FIG. 6 is a perspective view of the second form of the nasal cannulaassembly of FIG. 4 where the gases flow manifold part is disengaged fromthe face mount part, showing the manifold part can be fitted to eitherside of the face mount part.

FIG. 7 is a back perspective view of the second form of the nasalcannula of FIG. 4, showing a removable breathable pad on the inner sideof the face mount part that abuts the patients face.

FIG. 8 is a perspective view of a third form of the nasal cannulaassembly of the present invention, particularly showing a gases flowmanifold part that allows for the attachment of removable prongs.

FIG. 9 is a perspective view of the third form of the nasal cannulaassembly of the present invention, showing a strap and breathable padfittable to the manifold part of FIG. 8.

FIG. 10 is a perspective view of a first form of removable prongscapable of being attached to the manifold part of FIG. 8.

FIG. 11 is a perspective view of a second form of removable prongscapable of being attached to the manifold part of FIG. 8.

FIG. 12 is a perspective view of a patient wearing the nasal cannulaassembly of FIG. 4, showing the use of a neck tie to take some weight ofthe tubing and a head strap assisting in the maintaining of the assemblyto the patient's face.

FIG. 13 is a front view of a patient wearing a nasal cannula assemblypresent invention where the assembly is held to the patient's face withthe assistance of ear loops.

FIG. 14 is a side view of the patient and nasal cannula assembly of FIG.13.

FIG. 15 is a perspective view of a tracheotomy fitting.

FIG. 16 is a front view of a patient with a tracheotomy and fittingattached to a breathing supply where a neck tie or lanyard is used tosupport the conduit supplying gases to the patient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Whether used in a hospital environment or in a home environment, thenasal cannula assembly of the present invention will generally haveassociated three main pieces of apparatus. Firstly an active humidifierthat controls the temperature of a heater plate heating a body of waterto achieve a desired temperature and humidity of the gases beinghumidified. Secondly a transport conduit from the humidifier to thepatient is also required, which is preferably heated to reducecondensation, or “rain out”. Thirdly a nasal cannula designed to fitinto the nasal cavity of a patient or user and deliver humidified,pressurized gases.

Referring to FIG. 1 a humidifying circuit as might be used with thenasal cannula of the present invention is shown. A patient 1 isreceiving humidified and pressurized gases through a nasal cannula 20connected to a humidified gases transportation pathway or inspiratoryconduit 3 that in turn is connected to a humidifier 8 (includinghumidification chamber 5) that is supplied with gases from a blower 15or other appropriate gases supply means. The inspiratory conduit 3 isconnected to the outlet 4 of a humidification chamber 5 which contains avolume of water 6. Humidification chamber 5 is preferably formed from aplastics material and may have a highly heat conductive base (forexample an aluminium base) which is in direct contact with a heaterplate 7 of humidifier 8. The humidifier 8 is provided with control meansor electronic controller 9 which may comprise a microprocessor basedcontroller executing computer software commands stored in associatedmemory. Gases flowing through the inspiratory conduit 3 are passed tothe patient by way of the nasal cannula 20.

Controller 9 receives input from sources such as user input means ordial 10 through which a user of the device may, for example, set apredetermined required value (preset value) of humidity or temperatureof the gases supplied to patient 1. In response to the user set humidityor temperature value input via dial 10 and other possible inputs such asinternal sensors that sense gases flow or temperature, or by parameterscalculated in the controller, controller 9 determines when (or to whatlevel) to energize heater plate 7 to heat the water 6 withinhumidification chamber 5. As the volume of water 6 within humidificationchamber 5 is heated, water vapor begins to fill the volume of thechamber above the water's surface and is passed out of thehumidification chamber 5 outlet 4 with the flow of gases (for exampleair) provided from a gases supply means or blower 15 which enters thechamber through inlet 16. It should be noted that it is possible toobtain the relationship between the humidity of the gases inhumidification chamber 5 and the temperature of the heater plate 7.Accordingly, it is possible to utilize the heater plate temperature inan algorithm or a look-up table to determine the humidity of the gases.

The blower 15 may be provided with a variable speed pump or fan 2 whichdraws air or other gases through the blower inlet 17. The speed ofvariable speed pump or fan 2 may be controlled by a further controlmeans or electronic controller 18 (or alternatively the function of thiscontroller 18 could be carried out by the other controller 9) inresponse to inputs from controller 9 and a user set predeterminedrequired value (preset value) of pressure or fan speed via dial 19.

A heating element 11 may be provided within the conduit or tubing 3 tohelp prevent condensation of the humidified gases within the conduit.Such condensation is due to the temperature of the walls of the conduitbeing close to the ambient temperature, (being the temperature of thesurrounding atmosphere) which is usually lower than the temperature ofthe humidified gases within the conduit. The heater element iseffectively replaces the energy lost from the gases through conductionand convection during transit through the conduit. Thus the conduitheater element ensures the gases delivered are at an optimal temperatureand humidity.

Side Entry Nasal Cannula

The nasal cannula assembly of the present invention provides a patientwith a patient interface suitable for the delivery of high airflow, highhumidity gas flow to the patient's nasal cavity. A particular aspect ofthe nasal cannula of the present invention is the suitability for longterm therapy where the patient, for example, a patient suffering fromChronic Obstructive Pulmonary Disease (COPD), will wear the cannula forseveral hours per day over weeks, months and in some cases years.Therefore, for patients to accept use of nasal cannula under thesecircumstances the cannula need to be unobtrusive, comfortable to wear,noise free, suitable for wearing while sleeping, easy to clean and haveprongs that can generate Positive End Expiry Pressure (PEEP). Thecannula of the present invention may also be used for other therapiessuch as for Continuous Positive Airway Pressure (CPAP) therapy and thelike.

A first form of the nasal cannula assembly of the present invention isshown in FIGS. 2 and 3. This nasal cannula, generally indicated as 20,comprises a face mount part 21 including a pair of tubular nasal prongs22, 23 integrally molded with or removable attached to the face mountpart 21, and a gases flow manifold part 24 that is integrally moldedwith or attached to tubing 3, such as that described above.

The face mount part 21 and prongs 22, 23 are preferably molded fromsilicone or other flexible material as is known is the art of cannulaconstruction. The gases flow manifold part 24 is preferably made from ahard plastics material, although it may be manufactured in othersuitable materials.

The face mount part 21 is preferably integrally molded with the prongs22, 23 and is shaped to generally follow the contours of a patient'sface around the upper lip area. The inner side (not shown) of the facemount part 21 may be provided with a breathable pad, to be describedbelow. The outer side 25 of the face mount part 21 has molded in it anelongated oval recess 26 and two oval recesses 27, 28 that extendthrough the face mount part 21 and each meet the tubular passagewaysformed within each of the tubular prongs 22, 23.

The gases flow manifold part 24 is generally tubular in shape having asubstantially circular inlet (not shown) on one side that curves aroundto an elongated oval outlet 29. The circular inlet receives the end ofthe conduit or tubing 3, so that gases are supplied to the gases flowmanifold part 24 and are able to flow through the inlet and out theoutlet 29. The tubing 3 is preferably permanently fixed to the manifoldpart 24, but may be releasably attachable.

The outlet 29, being elongated and oval in shape, fits into theelongated recess 26 in a friction or snap fit engagement with themanifold 21, such that a substantial force is required to remove themanifold part 24 from the elongated recess 26. Further, as the facemount part 21 is flexible and the manifold part 24 made from a harderplastics material it is possible for the manifold part outlet 29 to beeasily pushed or forced into the elongated recess 26. When the manifoldpart 24 is engaged with the face mount part 21 and in use, gases flowfrom the tubing 3, through the gases flow manifold part 24 out itsoutlet 29, into each of the oval recesses 27, 28, into each of theprongs 22, 23 and into the patient's nares.

The face mount part elongate recess 26 and manifold part outlet 29 aresymmetrical in shape and configuration and therefore the manifold part24 is capable of being switched or flipped such that the tubing 3extends from either the left or right side of the patient's nares. Thismeans that the nasal cannula assembly 20 and associated tubing 3 arerelatively unobtrusive as the cannula 20 only requires a singlehorizontal side entry, not two entries as that of the prior art.

The nasal cannula assembly of the present invention is more comfortableto wear as it sits under the septum of the nose and supports the twonasal prongs. As the prongs are made in one molding of a soft materialsuch as silicone the prongs are easy to insert in the patient's naresand comfortable to the patient.

For a nasal cannula assembly to be suitable for wearing during sleepeach night the cannula must be noise free. Many prior art cannulas areprone to whistling. With a range of airflows generally being between 0to 40 liters per minute, although airflows of 60 liters per minute areenvisaged for the present nasal cannula, and with the air or gases beingsupplied to a single horizontal entry point it has proved difficult toprevent whistling. For this reason the face mount part 21 is contouredsuch that the pressure distribution within the face mount part 21 forceseven airflows up each nasal prong.

As the nasal cannula assembly of the present invention is likely to beused while a patient is sleeping, the cannula must be easily tailoredfor the patients sleeping arrangement. The cannula of the presentinvention supplies high flow humidified gases to the patient from eitherthe left side or the right side of the cannula thus allowing the minimumlength connection circuit to the bedside unit supplying the humidifiedgas. As the nasal cannula assembly of the present invention allows forthe horizontal entry of gases from either side the patient can configurethe unit as left or right entry for their particular sleepingarrangement. It is envisaged that the tubing 3 is approximately twometers in length to allow for added flexibility of the cannula.

Reference is now made to FIGS. 4 to 7 that show a second form of thenasal cannula assembly of the present invention. In this form the nasalcannula assembly 30 is of a substantially similar form to the first formdescribed above in relation to FIGS. 2 and 3, and has a face mount part32, a pair of nasal prongs 33, 34, gases flow manifold part 35 andtubing 3. The face mount part 32 and pair of nasal prongs 33, 34 arepreferably integrally molded as one piece from a soft plastics materialsuch as silicone, although in other forms the face mount part and prongsmay be separate, but capable of attachment together for use.

The nasal prongs 33, 34 are tubular in shape and may be consistent indiameter but may be shaped to fit the contours of the human nares.

A strap or strap attachment means 31 may be integrally formed orattached to the face mount part 32 in order to enable the nasal cannulaassembly 30 to be held in place about a patient's face.

The face mount part 32 has an open tubular recess 38 extending below thenasal prongs 33, 34 that is capable of receiving a gases flow manifoldpart 35 that is attached to or integrally formed with tubing 3. Thetubular passageways within the nasal prongs 33, 34 extend through theface mount part and into the recess 38. The gases flow manifold part 35is blocked at one end 39 but attached to the tubing at the other end andhas an elongate opening 37 that acts as an exit for gases received fromthe tubing 3. Due to the flexible nature of the material the face mountpart 32 is made from, and as the gases flow manifold part 35 is madefrom a hard plastics material, the gases flow manifold part 35 can bepushed through the tubular recess 38 in the face mount part 32 and theelongate opening 37 in the gases flow manifold part 35 meets with thetubular passageways of the prongs 33, 34. Therefore, in use, gasesflowing through the tubing and into the gases flow manifold part 35 exitthrough the opening 37 and into the tubular passageways in the prongs33, 34, then into the patient's nares.

In order to assist with maintaining the gases flow manifold part 35within the manifold recess 38 the manifold part 35 is provided with aninner recessed portion 60 and contoured lip areas 58, 59. When engagedwith the face mount part 32 the tubular body forming the recess 38 sitswithin the inner recessed portion 60 and the edges of the tubular bodyabut the lips 58, 59 formed on the manifold part 35.

Breathable Pad

A breathable pad may be supplied with any of the nasal cannulaassemblies described above. In particular, such a pad 36 is shown inFIG. 7 in the second form of the nasal cannula assembly as describedabove. It must be appreciated that a pad of this type may be providedwith any of the other two forms as herein described.

The pad is preferably attached to the inside surface of the face mountpart 32 that connects with the upper lip of the patient wearing thecannula. The pad 36, which is preferably made from an absorbent cloth,reduces the incidence of heat and moisture on the patient's upper lip,where the face mount part 32 sits against their face.

The pad 36 is preferably attached to the face mount part 32 by adhesive,for example, the pad could be supplied with a sticky backing thatadheres to the face mount part, so that the pad can be easily removedfrom the face mount part and replaced as necessary.

The pad reduces the effects of heat against the patient's skin andimproves hygiene, as any contaminants or cultures that may grow close tothe patient's skin, in the warm environment can be removed on removaland replacement of the pad.

Three Part Nasal Cannula

Referring now to FIGS. 8 to 11, a third form of the nasal cannulaassembly of the present invention is shown where the nasal cannulaassembly comprises three parts.

Firstly, a gases flow manifold part 40 is shown in FIG. 8 which isdesigned for either left or right hand orientation and provides asymmetrical flow to a pair of nasal cannula assembly prongs 41, 42 (seeFIG. 10 or 11).

Next, a pair of soft nasal prongs 41 or 42 are provided that are capableof being attached to the top of the gases flow manifold part 40 allowingfor a large range of different shaped and spaced prongs to be availableto the patient. Two such configurations of prongs 41, 42 are shown inFIGS. 10 and 11. The prongs 41 of FIG. 10 are narrow elongate tubularmembers 43, 44 of a substantially constant diameter that are fittableinto a patient's nares. The prongs are integrally molded with a body 45that is fittable with the gases flow manifold part 40 (see FIG. 8) byappropriate means, for example, friction or snap fit. The prongs 42 ofFIG. 11 are tapered tubular members 46, 47 molded to a body 48. Again,this body 48 is capable of being fitted (friction, snap or other) to thegases flow manifold part of FIG. 8. These prongs are preferably madefrom a soft plastics material such as silicon, although other suitablematerials may be used.

With the prongs being removable they are easily cleaned and could alsobe disinfected for second or subsequent use.

The third part to the third form of the nasal cannula assembly shown inFIGS. 8 to 11 is the face mount part 49 of FIG. 9. The face mount part49 comprises a head strap 53 attached to a pad 50, that may be a moldedor shaped substantially rigid pad, for example, made from a plasticsmaterial such as polypropylene. The pad 36 may include a breathablecloth pad on its surface that abuts a patient's face, similar to thatpad 36 described in relation to FIG. 7, or the head straps 53 may extendto sit behind the pad. The head strap 53 is preferably made from aflexible material, such as neoprene.

The plastic pad 50 is shown in FIG. 9 and has a plurality of apertures61 formed into to allow for heat and moisture to dissipate from thepatient's facial surface. The pad 50 has fastening means 51, 52 forholding the gases flow manifold part 49 in the correct position on theupper lip of the patient. The fastening means may be clips 51, 52 thatare fittable into complimentary recesses 54, 55, 56, 57 provided in oron the manifold part 40 (see FIG. 8), but other appropriate fasteningmeans may be provided with the cannula. An example of other fasteningmeans is a loop that is integrally molded as part of the prongs whichwraps around the face mount part and latches over a protrusion on themanifold part thus encapsulating the face mount part and holding theassembly together stably and securely. Another example of a fasteningmeans is a plastic Velcro™ type attachment where one side would attachto one side of the manifold part 40 and the other side to the plasticpad 50. For the fastening means shown in FIGS. 8 and 9 at least onerecess must be provided on either side of the manifold 40. In thepreferred form of the nasal cannula assembly two recesses 54, 55 areprovided on one side of the manifold 40 and two other recesses 56, 57 onthe other side of the manifold 40.

The attachment between the face mount part 49 and the manifold part 40allows for either left or right hand orientation of the manifold partand associated tubing.

It is envisaged the cannula of the present invention will be reusablefor several wearings on a single patient and as such the nasal cannulaassembly must be hygienic. It is envisaged that all the embodiments ofthe nasal cannula assembly of the present invention as herein describedcan be disassembled so that the cannula is easier to clean. The prongsand integrally attached parts are capable of being stored in a sterilesolution until reused, much like false teeth are currently stored whilenot in use.

With a single flow entry cannula there will be less condensate due tothe reduction in surface area for heat loss and thus the cannula of thepresent invention reduces the effects of condensation building in thetubing and cannula.

The detachable nasal cannula assembly described in relation to FIGS. 8to 11 allows a patient on long-term therapy to order their particularprong size but maintain a common tubing connection system right to thepoint of connection into the manifold under the nose.

In other forms of the nasal cannula assembly of the present inventionthe assembly may only be provided with one nasal prong fittable intoonly one of the patient's nares. The purpose of such an assembly withone prong is to allow for consecutive use of a nasogastric tube.Nasogastric tubes are generally inserted in one of a patient's nares andextend down into their stomach. For example, it may be necessary orideal for a patient to be fed by way of a nasogastric tube and to alsoreceive heated humidified gases. The nasal cannula assembly of thepresent invention having only one prong would allow this.

Flexible Extension Dry Tube

Often an unheated flexible section of tubing is placed proximal to thepatient to reduce torsion or pulling on the patient interface and reducepossible heat problems or over heating close to the patient. In order toreduce condensate forming in the unheated tubing, tubing can be providedthat has vapor transmission properties. Referring now to FIG. 12 thenasal cannula of the present invention (in particular, that of thesecond form described herein) may be provided with a short piece ofbreathable tubing 62 between the nasal cannula 30 and heated tubing 3.The tubing 62 is preferably made from a material that allows fortransmission of water, such as a hydrophilic material, for exampleSYMPATEX™.

Test results show the performance of a 420 mm length of breathable tube,operating with air input at an absolute humidity of 42.2 mg/L, anairflow of 10 liters per minute, in a room with ambient air at 22degrees C. and 50% RH, only lowered the air temperature to 37 and theabsolute humidity to 41.15 mg/L at the exit of the dry tube. Incomparison a 420 mm length of non-breathable but insulated polyethylenetube under exactly the same conditions also output air at 41.15 mg/L. Inthe breathable tube there was significantly less condensate measured,therefore, some of the humidity that would otherwise be lost ascondensate on the wall is being transmitted through the breathable wall.

The result of providing the short section of breathable tubing 62 isthat a majority of humidity in the gases is transported to the patient,and there is an insignificant and immeasurable loss of humidity throughthe breathable wall of the short tube 62, while condensate is reduced.The design of the high airflow high humidity system has been optimizedto deliver a breathable gas treatment to patients at temperaturesapproximating body temperature and fully saturated with water vapor forlong treatment periods. The use of an unheated breathable conduitproximal to the patient to provide a connection that is highly flexibleand avoids condensation by breathing would be expected to lower thehumidity of the gas treatment thereby decreasing the efficacy of thetreatment. These results are surprising and are counterintuitive and gosome way to explaining why the use of a breathable tube as a shortsection of tubing before the patient has been overlooked. This shorttube 62 is envisaged to be used with any tube delivering heated andhumidified gases to a patient.

Neck Tie

A neck tie or lanyard may be provided with the nasal cannula assembly ofthe present invention. FIG. 12 shows such a tie 63. The tie 63 ispreferably connected to the tubing 3 or connection 67 between the tubing3 and breathable tube 62. A toggle 64 is preferably provided with theneck tie 63 in order to adjust the neck tie's length. The neck tie hasthe purpose of taking some of the weight of the tubing 3 and preventsthe weight of the tubing 3 pulling on the nasal cannula assembly 30.This helps to prevent the prongs interfering with the very sensitivelining of the nasal passages. The loose fitting neck tie also provides aconvenient way of connecting the tubing 3 to the patient outside theblankets. This allows the patient to turn in the bed and avoids thetubing 3 overheating if placed under the blankets.

The tie or lanyard described may be used with any breathing apparatusthat supplies gases to a patient; for example it may be used with anasal or face mask or with a tracheotomy fitting or connector. When thetie or lanyard is used with such apparatus it takes the weight of theconduit(s) or tubing supplying gases to the mask, connector or cannulaeand helps reduce the pull on the mask, connector or cannulae.

FIGS. 15 and 16 show a tracheotomy fitting or connector that may utilizea neck tie or lanyard of the present invention. The tracheotomyconnector 69 attaches to a tracheotomy mount 72 that extends into atracheotomy tube (not shown) through hole in a patient's 68 neck andinto their airway passages. The connector 69 provides a direct couplingof a tracheotomy tube to the breathing supply of gases received througha conduit 71. Preferably the conduit 71 is constructed in a breathablematerial, similar to that described above, but may be a heated tube.

The connector 69 has the conduit 71 attached directly to it and alsoincludes an expiratory port 70 to allow for expiration of gases. Oninspiration no gases flow occurs out the port 70 due to the flow ofgases to the connector 69 being greater than a patient's peakinspiratory flow. Therefore, there is also no or very little entrainingof gases from the ambient air.

Excess weight on the tracheotomy tube may cause excess movement of thetube, with the risk of complications such as displacement orrecannulation of the tracheotomy, the formation of granulation tissue ormore seriously, stomal erosion. To obviate or reduce these problems atie or lanyard 73 can be connected to the conduit 71 or additionalconnector 74 (that may for example connector the conduit 71 to anadditional conduit 75 that supplies gases). The tie or lanyard 73transfers the weight of the conduits 71, 75 and connector 74 from thetracheotomy tube or mount 72 and distributes it onto the neck of thepatient leaving a minimal load directly on the tracheotomy tube or mount72. Preferably the tie or lanyard 73 is adjustable so that the tie orlanyard length can be altered to suit a patient's requirements.

Ear Loops

Orientation of a nasal cannula is an essential requirement to patientcomfort. If the nasal cannular is not held firmly in position, it canskew, placing unwanted load on the inside surfaces of the patient'snares. However, to overcome this head gear is often provided with nasalcannula, although, if the head gear is not tight the nasal cannula canstill move. This type of tight tension can then compromise patientcomfort with pressure on the head and face, while forcing the cannulafurther up the patient's nose. Ideally nasal cannula should attach tothe patient's face in a rigid manner, yet with low loading on the headand face.

Referring to FIGS. 13 and 14 nasal cannula attachment means may beprovided to hold the nasal cannula assembly 30 to the patient's face.The attachment means are preferably ear loops 65, 66 that are connectedto the straps 31 of the face mount part 32 of the nasal cannula assembly30.

The loops 65, 66 extend from the face mount part 32 around the patient'sears, and provide rigid anchoring when an inelastic material is used.The loops 65, 66 are preferably made from a thin, round cord with theends captured in plastic, and are preferably adjustable. The plasticends of the loops 65, 66 are inserted into purpose made cavities in thestraps 31, enabling adjustment of length for a comfortable, yet firmfit.

In use, to fit the nasal cannula assembly, a first loop (for example,loop 65) is placed over one ear, the nasal cannula assembly positionedon the patient's face and in their nose, then the other ear is passedthrough the second loop (for example, loop 66), so both loops sit snuglybehind the ears. This method of fitting the nasal cannula avoids theinitial discomfort of gases being blown into the patient's eyes when thecannula assembly is pulled down the face for fitting with otherheadgear. Fastening the nasal cannula in this method provides anattachment means that is horizontally secure with minimum tensionapplied to the ear connection loops. The ear loops have the addedadvantage for a patient lying on their back that there are no strapsbehind the back of the head that are moved by head movement on thepillow.

What is claimed is:
 1. A single side entry nasal cannula assemblyadapted to deliver gases to a patient's nares, the cannula assemblycomprising: a face mount part, including a tubular body having a lumenopening providing access to a lumen, the face mount part having a firstend and a second end, the opening being positioned between the first endand the second end of the face mount part, the face mount part furtherincluding at least one prong capable of being fitted into at least oneof the patient's nares, a single gases supply tube connected to thelumen opening of the face mount part, the single gases supply tubeextending toward only one of the first end and the second end of theface mount part, and no other gases supply tube extending from the otherof the first end and the second end of the face mount part, the facemount part configured to rest across the top lip of the patient, a firstlateral extension and a second lateral extension, each of the first andsecond lateral extensions extending laterally outward from the facemount part, a first support assembly coupled to the first lateralextension and the second lateral extension, the first support assemblyconfigured to engage a head of the patient and to at least partiallysupport the face mount part, and a second support assembly connected tothe gases supply tube and configured to support at least a portion of aweight of the gases supply tube, the second support assembly separateand independent from the first support assembly.
 2. The nasal cannulaassembly of claim 1 wherein the face mount part is molded from a softplastic material.
 3. The nasal cannula assembly of claim 1 wherein atleast the at least one prong is removably attached the face mount part.4. The nasal cannula assembly of claim 1 wherein the at least one prongis integrally molded to the face mount part.
 5. The nasal cannulaassembly of claim 1, wherein the second support assembly is a flexibletether that is connected to the gases supply tube and configured tosupport at least a portion of the weight of the gases supply tube whenworn by the patient.
 6. The nasal cannula assembly of claim 5, whereinthe flexible tether is positioned around a neck of the patient and theflexible tether is configured to support at least a portion of theweight of the gases tube by transferring at least a portion of theweight to the user's neck when worn by the user.
 7. The nasal cannulaassembly of claim 5, comprising a toggle that is connected to theflexible tether in order to adjust the length of tether.
 8. The nasalcannula assembly of claim 1 wherein the second support assembly isconfigured transfer some of the weight of the gases supply tube pullingon the nasal cannula assembly, while helping to prevent the nasal prongsinterfering with sensitive lining of the patient's nares.
 9. The nasalcannula assembly of claim 1 wherein the second support assembly isstructured to allow the gases supply tube to move relative to thepatient while maintain the at least one prong in an operable positionaligned with the nares of the patient.
 10. The nasal cannula assembly ofclaim 1 wherein the gases supply tube is a breathable tube.
 11. Thenasal cannula assembly of claim 1 wherein the first support assembly isa bifurcated headgear that includes a pair of side straps disposed onopposing sides of the patient's face when worn by the patient, each sidestrap bifurcating into an upper rear strap and a lower rear strap. 12.The nasal cannula assembly of claim 11 wherein the bifurcated headgearand the second support assembly together supporting the nasal cannulaassembly in an operable position.
 13. A single side entry nasal cannulaassembly adapted to deliver gases to a patient's nares, the cannulaassembly comprising: a face mount part having a first end and a secondend, the face mount part including at least one prong configured to befitted into at least one of the patient's nares and a body having afirst end and a second end, a single gases supply tube connected to theface mount part, the single gases supply tube extending from only one ofthe first end and the second end of the body, and no other gases supplytube extending from the other of the first end and the second end of thebody, the single gases supply tube comprising at least one flange, andthe single gases supply tube configured to engage the face mount partsuch that the at least one flange abuts a portion of the face mountpart, a headgear connected to the face mount part proximate both thefirst end and the second end of the face mount part and configured tohold the face mount part in an operable position, the headgear beingdistinct from the single gases supply tube, a flexible tether connectedto the gases supply tube and configured to support at least a portion ofthe weight of the gases supply tube on the patient, the flexible tetherseparate and independent from the headgear, and a coupler coupling thegases supply tube to the headgear, wherein in use, the headgear isconfigured to engage the patient's head and support a portion of theweight of the nasal cannula assembly, and the flexible tether isconfigured to support at least a portion of the weight of the gasessupply tube below the patient's head.
 14. The nasal cannula assembly ofclaim 13, wherein the flexible tether is configured to transfer at leasta portion of the weight of the gases supply tube to a neck of thepatient when worn by the patient.
 15. The nasal cannula assembly ofclaim 13, comprising a toggle connected to the flexible tether andconfigured to adjust a length of the flexible tether.
 16. The nasalcannula assembly of claim 1, further comprising a third support assemblycoupling the gases supply tube to the first support assembly.
 17. Thenasal cannula assembly of claim 13, wherein the at least one flangecomprises a first flange and a second flange, the single gases supplytube configured to engage the fact mount part such that the first flangeabuts a first side of the portion of the face mount part and the secondflange abuts a second side of the portion of the face mount part. 18.The nasal cannula assembly of claim 13, wherein a length of the singlegases supply tube overlaps a length of the body of the face mount partwhen the single gases supply tube engages the face mount part.
 19. Asingle side entry nasal cannula assembly adapted to deliver gases to apatient's nares, the cannula assembly comprising: a face mount partcomprising a protrusion, an opening providing access to a lumen, and atleast one prong in fluid communication with the lumen and configured tobe fitted into at least one of the patient's nares, the face mount parthaving a first end and a second end, a single gases supply tubeextending through the opening into the lumen of the face mount part, thesingle gases supply tube extending toward only one of the first end andthe second end of the face mount part, and no other gases supply tubeextending from the other of the first end and the second end of the facemount part, the single gases supply tube comprising a first flange and asecond flange, and the single gases supply tube configured to engage theface mount part such that the first flange abuts a first side of theprotrusion of the face mount part and the second flange abuts a secondside of the protrusion of the face mount part, the face mount partconfigured to rest across the top lip of the patient, a first lateralextension and a second lateral extension, each of the first and secondlateral extensions extending laterally outward from the face mount part,a first support assembly coupled to the first lateral extension and thesecond lateral extension, the first support assembly configured toengage a head of the patient and to at least partially support the facemount part, and a second support assembly connected to the gases supplytube and configured to support at least a portion of a weight of thegases supply tube, the second support assembly separate and independentfrom the first support assembly.
 20. The nasal cannula assembly of claim19, further comprising a third support assembly coupling the gasessupply tube to the first support assembly.
 21. A single side entry nasalcannula assembly adapted to deliver gases to a patient's nares, thecannula assembly comprising: a face mount part having a first end and asecond end, the face mount part including at least one prong configuredto be fitted into at least one of the patient's nares and a body havinga first end and a second end, a single gases supply tube connected tothe face mount part, the single gases supply tube extending from onlyone of the first end and the second end of the body, and no other gasessupply tube extending from the other of the first end and the second endof the body, the single gases supply tube comprising a first flange anda second flange, and the single gases supply tube configured to engagethe face mount part such that the first flange abuts a first side of aportion of the face mount part and the second flange abuts a second sideof the portion of the face mount part, a headgear connected to the facemount part proximate both the first end and the second end of the facemount part and configured to hold the face mount part in an operableposition, the headgear being distinct from the single gases supply tube,and a flexible tether connected to the gases supply tube and configuredto support at least a portion of the weight of the gases supply tube onthe patient, the flexible tether separate and independent from theheadgear, wherein in use, the headgear is configured to engage thepatient's head and support a portion of the weight of the nasal cannulaassembly, and the flexible tether is configured to support at least aportion of the weight of the gases supply tube below the patient's head.22. The nasal cannula assembly of claim 21, further comprising a couplercoupling the gases supply tube to the headgear.
 23. The nasal cannulaassembly of claim 21, wherein a length of the single gases supply tubeoverlaps a length of the body of the face mount part when the singlegases supply tube engages the face mount part.